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Mobility Robustness Optimization (MRO) is a use-case of Self-Organizing Networks (SON) for LTE that aims to optimize handover performance automatically. Conventional MRO algorithms tune handover parameters based on counts of handover failures and handover events. The algorithm requires many handovers per cell pair (e.g. 1000) to trigger a reliable adjustment. Thus it can result in a slow adaptation...
It has been observed that in overlaid 3G/2G networks certain user equipments (UE) may stay camped on 2G for long periods despite the fact there is available 3G coverage. In this paper we present a framework to enable network operators to identify these occurences, not easily recognized using counter-based observability. The proposed methodology relies on the post processing of performance monitoring...
The Long Term Evolution (LTE) network is currently being deployed on top of the legacy radio access technologies (RATs) such as the second generation (2G) or third generation (3G) mobile networks. Inter-RAT mobility robustness optimization (MRO) is one of the most important use cases for self-organizing network (SON). Unlike the manual optimization methods, an inter-RAT MRO algorithm adjusts the handover...
Starting with the introduction of LTE, there is a high operator initiated demand for management automation. All automation requirements on network configuration, optimisation, and failure recovery are subsumed under the term Self-Organising Networks (SON). Within a SON a potentially larger number of SON-Functions individually perform specific management tasks. To prevent conflicting behaviour among...
One major topic of research into SON technology is the coordination of SON use cases. Network operators expect a coordinated handling of the parameter and configuration changes submitted to the operating network by closed-loop SON use case implementations. Beside a published conceptual framework, SON coordination has already been treated in the literature, especially regarding the mobility load balancing...
Two main parameters influence the performance of Handover (HO) in Cellular systems, the Hysteresis (Hys) and the Time-To-Trigger (TTT). In Self-Organized Networks (SON) as has been proposed for LTE, the SON methods configure and optimize these two parameters to optimize HO performance. In this paper, we model the LTE HO procedure and propose an algorithm for self-configuration of the two HO trigger...
Mobility management is one of the basic features of terrestrial networks. It has also been identified as one self-organizing networks (SON) area suitable for automatic parameter adjustment. In this paper, we propose and evaluate a handover oscillation control mechanism for LTE. It adjusts the parameters per UE to address the UE-specific oscillatory behavior and mobility pattern. Field trials illustrate...
The success of communication service providers (CSPs) relies on efficient operational strategies for managing their networks, including the planning, optimisation and maintenance, in order to meet the desired Quality of Service (QoS), Quality of Experience (QoE) and business goals and requirements. Such business goals and requirements include, amongst others, the reduction of Operational and Capital...
Self-healing is a key functionality of Self-Organizing Networks (SON). There have already been promising research results on Degradation Detection and Root Cause Diagnosis. However, the complex task of Recovery Selection, i.e., the determination of the best recovery action for an uncertain diagnosis of a degradation considering the operational goals of the network operator, is rarely investigated...
Energy consumption in mobile networks, e.g. 3G networks, may be a substantial part of an operator's expenses. A large part of the total energy of the network is consumed by the radio access network. Today operators are saving energy by turning off carriers or cells during periods with low traffic by manually configuring on-off periods. At the same time, operators are seeking to increase cost efficiency...
Previous work on an energy detector (ED) has only analytically examined its performance over a flat-fading channel. But for the real environment, the channel should be assumed frequency-selective due to the high date rates. So in this paper we evaluate the performance of an ED over a frequency-selective fading channel. We show that the performance of the ED might improve because of the multipath environment...
We study transmission rate control and performance delay in cognitive radio (CR) links from a cross-layer perspective. We assume a hierarchical CR network where the secondary users (SU) access the spectrum band in an opportunistic and noncooperative way. The SU goal is to transmit a fixed-size file (fixed amount of data packets) during the sojourn time of the primary users (PU's) idle state. We assume...
Energy-based sensing (EBS) has been a topic of strong research in the last years due to its importance to Cognitive Radios (CRs). While EBS has been used in several works, different parameterizations have been adopted. In this work we compare different parameterization criteria to determine the decision threshold to the energy detector. We compare their performance through simulations by characterizing...
Sensing-throughput tradeoff under outage constraints has been studied before with an energy detector (ED). However, the ED does not work well in the presence of noise power uncertainty. So we study sensing-throughput tradeoff by using an autocorrelation detector (AD) for an OFDM signal. In this paper, we derive a closed form expression for the false alarm probability over both Nakagami-m and Rician...
In this paper, we propose a cooperative spectrum leasing scheme for cognitive radio networks, in which both the primary user (PU) and the secondary user (SU) target to maximize their individual utility. The PU leases a portion of its spectrum to the SU to obtain revenue when its QoS is guaranteed, and the SU rents the spectrum to achieve its target data rate. This cooperative spectrum leasing problem...
We address the use of single parity check product codes (SPCPC) for erasure recovery in opportunistic spectrum access schemes, where erasures are packets lost during a collision with the primary user (PU) due to sensing impairments (non detection). Our main motivation in using SPCPC is their low decoding complexity. We derive an analytical performance bound for these product codes when the PU's activity...
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